Maybe Apple will use this and tie it in to NOAA's National Weather Service in the USA.
http://www.weather.gov/view/nationalwarnings.php
It could save a significant number of lives if a tornado, flash flood, or forest fire was tearing through nearby.
Apple sells devices first and is middleman for developers second. Apple makes their money with devices.
If Apple doesn’t integrate a feature they would like to, the reason is much more likely that they don’t want to scare off developers, not (the small) lost revenue and (the even smaller) lost profit. (Considering the massive amounts of people writing software for iOS, that’s something Apple currently doesn’t have to worry about all that much.)
Apple will always want to make their devices more attractive for consumers. I don’t think that developers have priority for them (at least compared to consumers).
iOS 5 is already taking aim at Instapaper (Reading List), the entire ToDo category (Reminders), non-SMS messaging apps (iMessage), Zinio (Newsstand), half the camera apps out there, and a swath of Twitter apps [1]. You can almost bet if there is a swell of applications with similar features that Apple will wipe them all out in the next major version of iOS.
What's one more weather app? Apple is already taking aim at them by adding hourly forecasts to the built in weather app for iOS 5.